task-poky-tools: fix RDEPENDS_task-poky-tools-profile and add lttng-ust into it
Here the "_append" must appear just after RDEPENDS_task-poky-tools-profile, or
else, valgrind and lttng-ust won't be built into the target image.
At present we only build lttng-ust on
qemux86/qemux86-64/qemuppc/qemumips/emenlow/netbook since upstream liburcu
(which is required by lttng-ust) may not build on other platforms, like
qemu ARMv5te that poky uses now.
